There are NO exceptions regarding torture

In recent weeks many analysts and pundits have indicated that they oppose the use of torture, but would make exceptions under unusual cirumstances (ticking time bombs etc.)

The UN Convention on Torture, signed on behalf of the United States by Ronald Reagan, is quite clear about this in Article 2:

No exceptional circumstances whatsoever, whether a state of war or a threat or war, internal political instability or any other public emergency, may be invoked as a justification of torture.

Nor is it permissible to exempt from punishment the low-level underlings who administer the torture:

An order from a superior officer or a public authority may not be invoked as a justification of torture.

The latter was the essence of the Nuremberg trials.